Photoisomeric preparation of trans bis organosulfonyl ethylenes



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3,042,596 Patented July 3, 1962 3,042,596 PHQTOISQMERIC PRERARATION FTRANS BIS @RGANGSULFONYL ETHYLENES James D. Johnston, Baton Rouge, Lat,assignor to Pittsburgh Chemical Company, Pittsburgh, Pa., a corporationof Pennsylvania No Drawing. Filed July 15, 1960, Ser. No. 42,971 7Claims. (Cl. 204-458) This invention relates to the conversion of cisbis organosulfonyl ethylenes and haloethylenes to the correspondingtrans bis organosulfonyl ethylenes and haloethylenes.

Bis organosulfonyl ethylenes and haloethylenes have been found to begood fungicides, Johnston Belgian Patent 543,377, June 6, 1956, RaaschUnited States Patent 2,893,911 and Riden Belgian Patent 567,981, June14. 1958.

The trans isomer has been found in many cases to be superior to the cisisomer. Unfortunately, the normal procedures for preparing the hisorganosulfonyl ethylenes and haloethylenes either prepare the cis isomeror a mixture of cis and trans isomers containing a large proportion ofthe cis isomer.

Accordingly, it is an object of the present invention to convert cis bisorganosulfonyl ethylenes and haloethylenes to the corresponding transcompounds.

Another object is to convert cis bis alkyl sulfonyl ethylenes to thecorresponding trans compounds.

A more specific object is to convert cis bis n-propyl sulfonyl ethyleneto trans n-propyl sulfonyl ethylene.

Still further objects and the entire scope of applicability of thepresent invention will become apparent from the detailed descriptiongiven hereinafter; it should be understood, however, that the detaileddescription and specific examples, While: indicating preferredembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope or"the invention will become apparent to those skilled in the art from thisdetailed description.

It has now been found that these objects can be attained by treating acis bis organosulfonyl ethylene or haloethylene with bromine, preferablyin the presence of ultraviolet light.

As the starting cis organosulfonyl ethylenes and haloethylenes there canbe employed compounds having the formula where Q and Q are selected fromthe group consisting of alkyl having 1 to 18 carbon atoms, phenyl, loweralkyl phenyl, benzyl, chlorophenyl, bromophenyl, nitrophenyl andnaphthyl and X and X are selected from the group consisting of hydrogenand halogen. Preferably Q and Q are both alkyl groups of 2 to 5 carbonatoms and preferably both X, and X are hydrogen.

As typical examples of cis organosulfonyl ethylenes and haloethyleneswhich can be converted to the corresponding trans isomers there can beused 1,2-bis(methylsul-fonyl) ethylene; 1,2-bis (ethylsulfonyl)ethylene; 1,2-bis (n-propylsulfonyl) ethylene; 1,2-bis(isopropylsulfonyl) ethylene; 1,2-bis (n-butylsultonyl) ethylene;1,2-bis (isobutylsulfonyl) ethylene; 1,2-bis (t-butylsulfonyl) ethylene;1,2-bis (amylsulfonyl) ethylene; 1,2-bis (sec.buty1sulfonyl) ethylene;l,2-bis (hexylsulfonyl) ethylene; 1,2-bis (heptylsulfonyl) ethylene;

(octylsulfonyl) ethylene; (nonylsnlfonyl) ethylene; (decylsulfonyl)ethylene; (dodecylsulfonyl) ethylene; (octadecylsulfonyl) ethylene;(benzylsulfonyl) ethylene; (phenylsulfonyl) ethylene; (o-tolylsulfonyl)ethylene; (p-tolylsul-fonyl) ethylene; (m-tolylsulfonyl) ethylene;(Z-naphthylsulfonyl) ethylene; o-nitrophenylsulfonyl) ethylene;(p-nitrophenylsulfonyl) ethylene; (m-nitrosulfonyl) ethylene;(ochlorophenylsulfonyl) ethylene; (p-chlorophenylsulfonyl) ethylene;(m-chlorophenylsulfonyl) ethylene; (o-bromophenylsulfonyl) ethylene;(ethylsulfonyl) -1,2dichloroethylene; (methylsulfonyl)-1,2-dichloroethylene; (n-propylsulfonyl)-1,2-dichloroethylene;(n-propylsulfonyD-1,2-dibromoethylene; n-propylsulfonyl -1,Z-difiuoroethylene; (n-propylsulfonyl) -1,2-diiodoethylene; 1,2-bis(isopropylsulfonyl)-1,2-dichloroethyl-ene; 1,2-bis (n-butylsulfonyl)-1,2dichloroethylene; -1,2-bis (ethylsulfonyl)-1-chloro-2fiuoroethylene;

1- me thylsulfonyl) -2-( ethylsulfonyl) 1,2-dichloroethylene; l-(n-propylsulfonyl) -2- (n-butylsulfonyl) ethylene; 1,2-bisdodeeylsulfonyl) -1,2dichloroethylene; 1,2-bis methylsulfonyl)-1-chloroethylene; 1,2-bis (ethylsulfonyl)-1-chloroethylene; 1,2-bis(n-propylsulfonyl) -1-chloroethylene; 1,2-bis (n-propylsulfonyl)-1-brornoethylene; 1,2-bis (n-propylsulfonyl) -1-fiuoroethylene; 1,2-bis(isopropylsulfonyD-l-chloroethylene; 1,2-bis (nbutylsul-fonyl)-1-chloroethylene; 1,2-bis (isobutylsulfonyl)-1-chloroethylene; 1,2-bis(sec. butylsulfonyl) -1-chloroethylene; 1,2-bis (tert. butylsulfonyll-chloroethylene; 1-methylsulfonyl-2-butylsulfonyl l-chloroethylene;1-propylsulfonyl-2-butylsulfonyl ethylene; 1,2-bis(octylsulfonyl)-l-chloroethylene;

1,2-bis l,2-bis l,2-bis 1,2-bis 1,2-bis 1,2-bis 1,2-bis 1,2-bis 1,2-bis1,2-bis 1,2-bis 1,2-bis 1,2-bis 1,2bis 1,2-bis 1,2-bis 1,2-bis 1,2bis1,2-bis 1,2-bis 1,2-bis 1,2-bis 1,2-bis 1,2-bis and 1,2-bis(octadecylsulfonyl)-l-ehloroethylene.

Since most of the cis organosulfonyl compounds set forth above aresolids, it is desirable to carry out the isomerization in the presenceof a solvent. The preferred solvents are hydrocarbons andhalohydrocarbons such as benzene, toluene, Xylene, ethylene dichloride,1,1,2-trichlorethane, carbon tetrachloride, carbon tetrabromide,trichloroethylene, methylene chloride, perchloroethylene and chloroform.

Only a few drops of bromine need be added, although considerably morebromine can be employed but this is not preferred for economic reasons.

The ultraviolet irradiation can be carried out with a conventionalsunlamp or any other source of ultraviolet light. Ultraviolet lightirradiation of the cis isomer in the absence of bromine did not causeisomerization.

The isomerization reaction goes satisfactorily at room temperature buteither elevated or reduced temperatures can be employed.

In the specification and claims, all parts and percentages are by weightunless otherwise indicated.

Example 1 20 grams of bis (p-tolylsulfonyl) ethylene (35% cis isomer andtrans isomer) and ml. of chloroform were placed in a flask and two dropsof a concentrated bromine solution in carbon tetrachloride were added.The orange color persisted even on Warming. The flask was irradiatedwith a sunlamp and the orange color was rapidly dissipated with theformation of a precipitate. More bromine solution was added slowly untilthe orange color was not discharged on standing. The product wascollected by filtration, washed with chloroform until white and dried.There were collected 12.8 grams of trans 1,2-bis (p-tolylsulfonyl)ethylene, melting point 225-227 C. There were recovered by concentrationof the mother liquor an additional 6.2 grams of the trans compound.

Example 2 25.5 grams of the pure cis 1,2-bis (n-propylsulfonyl) ethylenewas dissolved in 150 ml. of carbon tetrachloride and a few drops ofbromine added. The mixture was then irradiated with an ultraviolet lightlamp (sunlamp). A copious precipitate formed as soon as the light sourcewas turned on. After fifteen minutes, this precipitate was removed fromthe filtrate by filtration and air dried free of carbon tetrachloride.The precipitate Weighed 25 grams. The melting point of the precipitatewas 155 156 C. which is the melting point of pure trans 1,2-bis(propylsulfonyl) ethylene. (The cis isomer melts at 42-44 C.)

The same isomerizat-ion was observed when the carbon tetra-chloride inExample 2 was replaced by benzene, ethylene dichloride,1,1,2-trichlorethane, trichloroethylene, methylene chloride andperchloroethylene.

The results obtained are surprising since other methods which have beenemployed for converting cis isomers to trans isomers are ineffective.Among such procedures which do not work with the organosulfonylethylenes are heating the cis isomer to 150 C. for 28 hours.

What is claimed is:

4 1. The method of converting the cis isomer of a compound having theformula S Q2 1% X2 0 0 wherein Q and Q are selected from the groupconsisting of alkyl, aryl, haloaryl and nitroaryl and X and X areselected from the group consisting of hydrogen and halogen to the transisomer comprising treating said cis isomer with bromine in the presenceof ultraviolet light.

2. A method according to claim 1 wherein the cis compound is dissolvedin a solvent.

3. A method according to claim 2 wherein X and X are both hydrogen.

4. The method of converting the cis isomer of a bisalkylsulfonylethylene to the trans isomer comprising treating said cis isomer withbromine in the presence of ultraviolet light.

5. A method according to claim 4 wherein the cis compound is dissolvedin a solvent.

6. A method according to claim 5 wherein the alkyl groups have 2 to 5carbon atoms each.

7. The method of converting cis bis (n-propylsulfonyl) ethylene to transbis (n-propylsulfonyl) ethylene comprising treating said cis isomerwhile dissolved in a solvent with bromine in the presence of ultravioletlight.

References Cited in the file of this patent UNITED STATES PATENTS2,893,911 Raa-sch July 7, 1959 OTHER REFERENCES Journal of the AmericanChemical Society, vol. 59 (1937), page 1155.

1. THE METHOD OF CONVERTING THE CIS ISOMER OF A COMPOUND HAVING THEFORMULA